Smoking, gender, and age as risk factors for site-specific intraoral squamous cell carcinoma. A case-series analysis.

BACKGROUND: Studies assessing risk factors for oral cancer do not generally report results for specific oral sites. The purpose of the current study was to examine differences in the distribution of age, gender, and tobacco use by intraoral site in a series of oral cancer cases.

METHODS: Information on gender, age at diagnosis, and lesion location was obtained for all incident cases of oral squamous cell carcinoma diagnosed through the University of Connecticut Oral Pathology Biopsy Service during the period 1987-1991 (N = 150). Information on tobacco use was obtained through a telephone interview or from medical or dental records.

RESULTS: The tongue, floor of the mouth (FOM), and gingiva, respectively, were the most commonly affected sites. The male-to-female ratio was greatest for FOM cancer (3.4) and lowest for gingival cancer (0.5). The mean age at diagnosis did not differ significantly by site. The percentage of smokers among cases of FOM, tongue, and gingival cancer was 97%, 64%, and 50%, respectively. When multiple logistic regression was used to compare FOM and gingival cancer, gender and smoking remained significant predictors. The odds of smoking among patients with FOM cancer were 32 times the odds of smoking among patients with gingival cancer (odds ratio for age, gender adjusted = 32.6, 3.3-323.5).

CONCLUSIONS: The findings suggest that cancer of the FOM is more strongly associated with smoking than is cancer of the gingiva and, perhaps, the tongue. The reported results should be interpreted cautiously in light of study limitations, which include the absence of information on alcohol consumption and lack of a noncancer control group.